Red versus yellow: the fault lines in Thai politics

This weekend, at least 21 people were killed in clashes between security forces and so-called Red Shirts protesters. The Red Shirts, supporters of ousted former prime minister Thaksin Shinawatra, have been calling for new elections.But any comeback by Shinawatra would be an extremely divisive move - in the past, many Thais have staged mass protests AGAINST the former leader.